1. Field of the Invention
This invention relates to a system for controlling contactless IC (integrated circuit) cards. This invention also relates to a method of controlling contactless IC cards.
2. Description of the Related Art
In a prior-art contact IC card control system, IC cards communicate with readers/writers when being inserted thereinto. In each of the readers/writers, the type of an IC card placed thereinto is detected as follows. When the IC card is reset, for example, when the IC card is subjected to a power-on resetting process, the IC card transmits a reset notice to a reader/writer. The reset notice contains information of the type of the IC card. The reader/writer identifies or detects the type of the IC card in response to the reset notice transmitted from the IC card. Then, the reader/writer implements the following processes related to the identified IC card. First, the reader/writer assigns a logical address to the IC card in accordance with the identified type thereof. Second, the reader/writer controls the reading and the writing of information from and into the IC card in response to the logical address. The assignment of the logical address to the IC card is canceled when the IC card is reset by turning off the power supply.
In a contactless IC card control system, a reader/writer has a communication service area (a communication coverage). The reader/writer can communicate with an IC card or IC cards in the communication service area by radio.
In a conceivable contactless IC card control system, a reader/writer assigns different logical addresses to respective IC cards in its communication service area. The reader/writer feeds power to the IC cards by radio. When the power supply of the reader/writer is turned off, power feed to all the IC cards is suspended so that the assignment of the logical addresses thereto is canceled at once. Accordingly, in the conceivable contactless IC card control system, it is difficult to cancel the assignment of the logical address to one of the IC cards. In addition, it is difficult to control IC cards, the number of which exceeds the number of usable logical addresses.
Generally, as the number of different logical addresses increases, the number of bits representing each logical address increases. An increase in the number of address-representing bits is disadvantageous to signal processing which includes address processing.
It is a first object of this invention to provide a system for controlling contactless IC (integrated circuit) cards which can cancel the assignment of a logical address to one of the IC cards.
It is a second object of this invention to provide a method of controlling contactless IC (integrated circuit) cards which can cancel the assignment of a logical address to one of the IC cards.
It is a third object of this invention to provide a system for controlling contactless IC (integrated circuit) cards, the number of which exceeds the number of usable logical addresses.
It is a fourth object of this invention to provide a method of controlling contactless IC (integrated circuit) cards, the number of which exceeds the number of usable logical addresses.
A first aspect of this invention provides a contactless IC card control system comprising first means (200) for causing a reader/writer (RW) to require identification information pieces of respective plural IC cards (A, B, C); second means (310) for causing the plural IC cards to return the respective identification information pieces in response to the requirement by the first means; third means (212, 213, 220, 230, 320) for assigning logical addresses to some IC cards among the plural IC cards respectively to cause the reader/writer to select the some IC cards among the plural IC cards in response to the return of the identification information pieces by the second means; fourth means (240, 241, 250, 340, 370) for controlling the some IC cards selected by the reader/writer; fifth means (260, 261, 360) for causing the reader/writer to cancel the assignment of the logical address to one of the some IC cards; sixth means (262, 263, 320, 330) for assigning the logical address, the assignment of which has been canceled by the fifth means, to an IC card among the plural IC cards to which any logical address has not been assigned yet; and seventh means (264, 340, 370) for controlling the IC card to which the logical address has been assigned by the sixth means.
A second aspect of this invention provides a method of controlling contactless IC cards which comprises the steps of causing a reader/writer (RW) to require identification information pieces of respective plural IC cards (A, B, C); causing the plural IC cards to return the respective identification information pieces in response to the requirement by the reader/writer; assigning logical addresses to some IC cards among the plural IC cards respectively to cause the reader/writer to select the some IC cards among the plural IC cards in response to the return of the identification information pieces by the plural IC cards; controlling the some IC cards selected by the reader/writer; causing the reader/writer to cancel the assignment of the logical address to one of the some IC cards; assigning the logical address, the assignment of which has been canceled by the reader/writer, to an IC card among the plural IC cards to which any logical address has not been assigned yet; and controlling the IC card to which the logical address has been assigned by the immediately-preceding step.
A third aspect of this invention provides a contactless IC card control system comprising first means for assigning a first logical address to a first IC card; second means for assigning a second logical address to a second IC card, the second logical address differing from the first logical address, the second IC card differing from the first IC card; third means for canceling the assignment of the first logical address to the first IC card while maintaining the assignment of the second logical address to the second IC card; and fourth means for, after the assignment of the first logical address to the first IC card is canceled by the third means, assigning the first logical address to a third IC card which differs from the first and second IC cards.
A fourth aspect of this invention provides a contactless IC card control system comprising first means for assigning a first logical address to a first IC card; second means for assigning a second logical address to a second IC card, the second logical address differing from the first logical address, the second IC card differing from the first IC card; third means for controlling the first IC card in response to the first logical address; fourth means for, after the third means controls the first IC card, canceling the assignment of the first logical address to the first IC card while maintaining the assignment of the second logical address to the second IC card; and fifth means for, after the assignment of the first logical address to the first IC card is canceled by the fourth means, assigning the first logical address to a third IC card which differs from the first and second IC cards.
A fifth aspect of this invention is based on the fourth aspect thereof, and provides a contactless IC card control system further comprising sixth means for, after the fifth means assigns the first logical address to the third IC card, controlling the third IC card in response to the first logical address.
A sixth aspect of this invention is based on the fourth aspect thereof, and provides a contactless IC card control system further comprising sixth means for controlling the second IC card in response to the second logical address.